Rotary switch mechanism



July 10, 1928. 1,677,008

G. R. TOWNSEND ROTARY SWITCH MECHANISM Filed Dec. 12, 1925 lnven r George RTownsend;

9 Hi5 Attorn eg.

Patented July 10, 1928.

GEORGE R. TOWNSEND, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELEC- PATE,

TRIC COMPANY, A CORPORATION OF NEW YORK.

ROTARY SWITCH MECHANISM.

' Application filed December 12, 1925.

The present invention provides an improved form of switch mechanism in which a circuit controlling member is operated responsively to the direction of rotation of a rotatable member through the agency of a yielding viscous connection.

Although of general utility, my improved rotary switch mechanism is particularly adapted to be operated by a reversible elec tric motor or other rotating apparatus and may be arranged to open or close an elec the above character ordinarily has depended upon the direct frictional engagement of a continuously rotating member operated by the motor with a switch operating member which is rotatable only to a limited degree. When such a switch is employed with high speed motors the heating and wear produced by the frictional engagement between the driving and the driven switch members upon continued rotation of the motor becomes excessive and eventually may cause the rotational switch mechanism to fail or operate improperly and unsatisfacto-rily.

In accordance with the present invention this difficulty is overcome by interposing a yielding viscous fluid connection between the continuously rotating member and the switch operating member having limited rotation so as to form an operative connection r therebetween depending entirely upon the viscosity of the fluid. In this way heating and frictional wear upon the rotating memhers is eliminated quite effectively even when tht continuously rotatable member is driven at high speed for prolonged intervals. However, the viscous fluid forms a flexible connection between the two members such that a reversal in rotation of the driving member is immediately transmitted to the driven member. Furthermore, when a heavy Serial No. 75,147.

petroleum oil is used as the viscous connection between the two rotatable members, the invention readily provides an eificient system of lubrication for the bearings of the rotatable members.

A preferred form of rotary switch mecha- IllSlIl embodying the invention is illustrated in the accompanying drawings, in which Fig. 1 is a perspective view of the switch mechanism with certain parts thereof omitted for the sake of clearness and Fig. 2 is a vertical section showing the operative relation of the various parts of the switch mechanism of Fig. 1 when completely assembled.

The rotary switch mechanism illustrated in the drawing comprises essentially a movable contact or bridging member 10 which is operable between the two sets of stationary contacts 11 and 12. The movable contact 10 is mounted upon an arm 13 which preferably is formed of insulating material and is carried by the rotatable member or disc 14 which is limited in its rotational movement by the engagement of contact 10 with either of the stationary contacts 11 and 12. The disc 14 is operated by the continuously rotating member or disc 15 which isdriven by the shaft 16. The shaft 16' may be driven by an electric motor or other continuously rotating apparatus.

As better shown in Fig. 2, the hubs of the rotatable discs 14 and 15 are mounted concentrically upon the shaft 16 which runs in suitable bearings 17 and 18 inserted in the end walls of the enclosing casing 19. In the preferred form of construction shown the disc 14 is rotatably mounted upon the hub 20 of the disc 15 and is held in position by the collar 21 and the tapering pin 22 whic also serves to fixedly secure the disc 15 to the shaft 16. The collar 21 maintains the discs 14 and 15 in operative relation with the opposing radial surfaces of the two discs separated by a slight distance, such for example as 1/64".

In order to operatively connect the driven disc 14 with the driving disc 15, the enclosing casing 19 is partially filled with a viscous fluid such as a heavy petroleum oil 23. The pipe elbow 24 serves as a convenient filling spout and level indicator, while the pipe groove 26 which intersects a radial slot 27 formed in the lower portion of the disc. The slot permits a ready flow of the viscous fluid or oil 23 into the space between the lower portions of the discs 14 and 15 and the circumferential groove 26 allows the oil to flow readily into the remaining space between the discs when the disc 15 is rotated'in either.

direction. The small opening 28 into the channel 29 conducts the oil from the circumferential groove 26 to the bearing of the disc 14 upon the hub 20 of disc 15 and thereby furnishes a plentiful supply of lubricant to this bearing. The oil thrown upward by the rotation of disc 15 is confined by the enshrouding portion of disc 14. A part of the oil is supplied to the shaft bearing 17 through the oil channel 30 and is returned to the bottom portion of the casing by the outlet channel 31. The bafile 32 formed of a suitable material such as felt, fibre, or the like is spring pressed against the upper surface of shaft 16 to prevent the oil from working out beyond the removable cover plate 33 through which the shaft 16 extends. The end bearing 18 for the shaft 16 preferably is of the completely closed type, and is arranged to be supplied with lubricating oil through the oil channel 34 by the oil ring 35. i

In order to obtain a compact structure and utilize to the best advantage the space within the casing 19, the stationary contacts 11 and 12 are mounted upon an insulating base 36 which is held by the supports 37 just above the hubs of the discs 14 and 15, and well below the top of the discs. This permits the overall dimensions of the container 19 to be only slightly greater than the diameter of the disc 14. A plate 38 is secured between the contact operating arm 13 and the disc 14 and carries an adjusting weight 39. The weight 39 may be adjusted to diflerent positions on the plate 38 to counterbalance the weight of the contact 10 and the operating arm 13 or bias the contact 10 out of engagement with the stationary contacts 12 and 13 as desired. With the weight 39 proportioned to overbalance the weight of the contact 10 and the arm 13, it serves to bias contact 10 out of engagement with either the stationary contacts 11 or 12 when placed upon the opposite ends of plate 38. However, it will'be evident that other means such as springs or the like, may be employed if desired for suitably counterbalancing and biasing the contact 10.

The switch casing 19 is provided with supporting feet 40 and with a removable cover 41 to permit ready access to the switch contacts and the operating mechanism. The opening 42 is screw threaded to receive the conduit for the control wires connectedto the stationary contacts 11 and 12.

From the foregoing description it will. be

apparent that with the rotation switch constructed and arranged as shown in Figs. 1 and 2 of the drawing, the'disc 14 is operatively connected through the viscous fluid to the disc 15 so as to readily follow the rotation of the shaft 16 in either direction and thereby operate the contact 10 into engagement with either the contacts 11 or the contacts 12. The stationary contacts prevent further rotation of the disc 14 but the viscous connection permits the rotation of disc 15 to continue in either direction indefinitely and at high speed without appreciable heating or wear between the discs. The oil carried up by the disc 15 during continued rotation thereof supplies abundant lubrication to the bearing of the disc 14 and also the bearing 17 of the shaft 16. .At the same time the oil ring 35 lubricates the shaft bearing 18.

In case the shaft 16 and the disc 15 are rotated in a clockwise direction to carry the contact 10 into engagement with the contacts 12, the weight 39 may be adjusted so as to.

just counterbalance the disc 14 and the contacts 10. Thus, when the clockwise rotation of shaft 16 and disc 15 is stopped and reversed the viscous connection causes the disc 14 to readily follow the initial reverse movement of the disc 15 and immediately carry the contact 10 out of engagement with the contacts 12. If the reversed or counterclockwise rotation of shaft 16 and disc 15 is continued, the rotation of the disc 14 likewise is continued to carry the contact 10 into engagement with. the contracts 11. With the weight 39 secured to the other end of plate 38the contact 10 may be counterbalanced when in engagement with the contacts 11. In either case the weight 39 effectively overbalances the contact 10 when the latter disengages the stationary contacts and thereby prevents extraneous jars or vibrations from causing the return of contact 10 into engagement with the contacts.

In case the weight 39 is so proportioned that it materially overbalances the weight of contact 10 when the latter is in engagement with contacts 12, the contact 10 is disengaged from the contacts 12 somewhat before the clockwise rotation of disc 15 is stopped and reversed, depending upon the biasing force exerted by the Wei ht 39.

With the weight 39 at the other end off the plate 38, the contact 10 is counterbalanced or biased out of engagement with the contacts 11 in substantially the same manner as just described.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A direction switch comprising a shaftmounted for continuous rotation in either direction, a pair of independently rotatable discs mounted in opposing spaced relation 'upon said shaft with the hubs. of the discs I" inner hub to the shaft and for limiting the axial movement of the outer hub, switch mechanism connected-to be actuated upon movement of the disc having the outer hub, and a viscous fluid adapted to flow between the concentric hubs and the adjacent faces of said discs to form a yielding torque transmitting connection therebetween to operate said switch mechanism upon a reversal in rotation of said shaft.

2. A direction switch comprising a c'asing, a shaft extending through one wall of the casing andmounted for rotation therein, a disc having a hub surrounding said shaft and fixedly secured thereto, a second slotted disc rotatably mounted upon the hub of the first disc in spaced relation therewith and having a flanged extension on the periphery thereof forming a housing surrounding the periphery of the first disc, switch mechanism mounted within said casing and ad jacent said shaft and having a movable switch element mounted upon the periphery of said second disc to be operated upon rotation thereof between predetermined limits, a viscous l'luid in said casing and immersing the bottom portions of said discs to be carried between the hubs and the adjacent faces thereof and confined by said housing, said fluid having a sufliciently high Viscosity to transmit torque from the first disc to the second disc to operate the switch mechanism upon a 'reversal in the rotation of said shaft.

3. A direction switch comprising a. casing, a shaft extending through one wall of the casing and rotatably mounted therein, a disc having a hub fixedly mounted upon said shaft within the casing, a second disc having a radial slot therein and a hub rotatably mounted upon the hub of the first disc and provided with a flanged extension on the periphery thereof forming a housing surrounding the periphery of the first disc, a switch mechanism mounted within the cas ing and connected to be actuated upon rotation of the second disc between predetermined limits, and a viscous oil in the bottom ofthe casing and immersing the bottom portion of said discs to be drawn through said slot and carried between the hubs and the adjacent faces of the discs and confined by said housing to form a yielding driving connection therebetween to operate said switch mechanism upon initial rotation of the shaft in either direction and to supply lubrication to the said shaft bearing and to the hub bearing between said discs.

In witness whereof, I have hereunto set my hand this 11th day of December, 1925 GEORGE R. TOWNSEND. 

